This invention relates generally to lenses with optical filters and, more particularly, to a reading lens for providing vision-corrective magnification while filtering impinging light according to a predetermined spectrum and inhibiting predetermined glare characteristics.
Many people require some type of magnification in order to read clearly. Rather than purchasing prescription lenses, some people choose to obtain generic reading glasses, commonly referred to as xe2x80x9creadersxe2x80x9d. The mass production of lenses for readers makes them very affordable. However, readers are less effective when utilized in outdoor environments, particularly in intense sunlight due to glare, reflections, and wavelengths of light that are not conducive to reading.
Various filters have been proposed in the art for regulating the passage of predetermined wavelengths of light through an optical medium. Although assumably effective for their intended purposes, the existing devices do not provide vision-corrective refraction along with spectral filtration of wavelengths not conducive to reading. Further, existing readers do not provide eye protection means including tinting, a polarized filter, and an anti-reflective coating.
Therefore, it is desirable to have a reading lens to be held by a sunglasses lens frame which includes at least a portion having a vision corrective light-refracting curvature. Further, it is desirable to have a reading lens which includes a spectral filter for inhibiting wavelengths of light that are not optimally conducive to reading. In addition, it is desirable to have a reading lens that includes a polarized filter and an anti-reflection coating to reduce disadvantageous glare characteristics encountered in outdoor sunlit environments.
A reading lens for blocking predetermined wavelengths and glare characteristics of light that are not conducive to reading in a sunlit environment includes a substantially transparent optical element, at least a portion of which includes a predetermined light-refracting curvature. This refractive curvature provides magnification of images viewed through the optical element. The optical element is adapted to be mounted within the lens frame of a pair of sunglasses. Further, the optical element includes a spectral filter for allowing predetermined percentages of particular wavelengths of light to pass therethrough. For example, only enough of the wavelength of light associated with the color blue is allowed to pass so as to maintain color identification. This is in recognition that blue light has the shortest wavelength and is prone to scattering, which reduces visual sharpness. The reading lens further includes a particular amount and distribution of tinting according to a predetermined light transmission ratio and includes a polarized filter and anti-reflection coating, whereby to minimize eye strain or damage.
Therefore, a general object of this invention is to provide a reading lens for magnifying an image viewed therethrough and to minimize wavelengths and glare characteristics that are not conducive to reading.
Another object of this invention is to provide a reading lens, as aforesaid, having a light transmission ratio that blocks a predetermined percentage of impinging light so as to reduce sunlight intensity.
Still another object of this invention is to provide a reading lens, as aforesaid, that blocks all ultraviolet light wavelengths.
Yet another object of this invention is to provide a reading lens, as aforesaid, having a polarized filter to block light reflecting off of horizontal surfaces.
A further object of this invention is to provide a reading lens, as aforesaid, having an anti-reflective coating to inhibit reflection of light by an inner surface of the lens.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.